Author Topic: AE 90 capacitor markings  (Read 813 times)

unbeldi

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AE 90 capacitor markings
« on: March 26, 2017, 11:29:47 AM »
The following picture was posted by user KaiserFrazer67 (http://www.classicrotaryphones.com/forum/index.php?topic=17876.msg184605#msg184605) of a condenser in his AE 90, stamped 10-66-16.



The condenser shows the marking "EF"  under the specifications, and "CF-4" stamped onto a side.

What implication has this for our decoding research?

I would think the marking EF was stamped at time of manufacture when the specification was stamped onto the large side of the unit.
Following manufacture, one would expect the parts to be sent to quality control for testing.  I would expect the second type of stamp was applied then.   However, if these codes indeed represent dates, according to our main hypothesis, then it seems that the should be closer together, or identical, and if different, the QC stamp should have a higher value.  Yet, C is smaller than E.     If "F" represents the larger time period, e.g. a year, then it does not precisely fit into the scheme proposed that starts in 1958 with "A".  Close, but off.



Offline AE_Collector

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Re: AE 90 capacitor markings
« Reply #1 on: March 26, 2017, 12:06:45 PM »
That is interesting....or maybe even disappointing! Another conundrum :(

The year of the phone (1966) versus our theory that F should be 1963 isn't a problem due to this statement in Toms first post about his phones:

Center AE 90:  NB 92219  CXX-   Date code:  10-66-16

CXX means a phone shipped from AE without a ringer installed. Thus this ringer was added from the Telco's stock when the phone was installed.

Asked Tom in the topic about the white 90 if he can find more two letter codes on the 90.

Terry
« Last Edit: March 26, 2017, 12:19:10 PM by AE_Collector »

unbeldi

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Re: AE 90 capacitor markings
« Reply #2 on: March 26, 2017, 12:23:12 PM »
The CF-4 marking could possibly also be for the combination of the condenser and ringer.
I believe, each ringer was tuned with its capacitor in place, as a complete ringing bridge.  Still it does not explain the sequence of CF after EF.

Offline AE_Collector

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Re: AE 90 capacitor markings
« Reply #3 on: March 26, 2017, 01:02:45 PM »
It seems surprising to me that the letters stamped on the large side of the condenser usually (always?) appear to be stamped during the manufacture of the condenser. Likely the same for other components as well such as the capsules. Thus they aren't being stamped on during assembly which admittedly would be a bunch of fooling around with ink slowing everything down. Therefore, it seems more likely that parts with two letter codes were stamped sometime before assembly.

Could they have been stamping these items sort of like a warranty start or stop date, in anticipation of the likely timeframe that the phone would be complete or maybe in the end customer (telco's) hands? Maybe then JUST the two letter code on the base along with the number (assembly crew/line) was stamped once the phone was complete and tested or whatever QC checks were done. Thus this stamping was more likely a more accurate date of completion. Of course in this example (Toms AE90) the bases were now being stamped with an actual date rather than two letter codes.

This could somewhat explain the CF ink stamp on the EF Condenser. Unusual to have the CF-4 on the condenser as well as the EF but this ringer assembly was quite likely assembled, tested and boxed up as a separate item to ultimately be installed in phones shipped without a ringer which may have led to the full letters/number being stamped onto it.

Terry
« Last Edit: March 26, 2017, 01:18:48 PM by AE_Collector »

unbeldi

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Re: AE 90 capacitor markings
« Reply #4 on: March 26, 2017, 01:49:36 PM »
It seems surprising to me that the letters stamped on the large side of the condenser usually (always?) appear to be stamped during the manufacture of the condenser. Likely the same for other components as well such as the capsules. Thus they aren't being stamped on during assembly which admittedly would be a bunch of fooling around with ink slowing everything down. Therefore, it seems more likely that parts with two letter codes were stamped sometime before assembly.

Well, it is just a speculation that they were stamped during manufacture, but they always seem aligned neatly with the specification, while codes on the sides often are not aligned with any edges, thus being manually applied.

Offline AE_Collector

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Re: AE 90 capacitor markings
« Reply #5 on: March 26, 2017, 01:59:17 PM »
Presumably the condensers were being made by AE, not for AE so they probably had a reasonably short turn around time from manufacture to installation. An "in the future" date at manufacture would still make it possible to determine timeline if there was a problem and fairly closely dates the parts in the phones. It explains the instances of various components that have close but not identical two letter codes.

I know little about date codes on things in general but recall NorTel components in the 80's and 90's all having warranty expiry stickers that seemed to be dated maybe 16 months into the future from manufacture so they likely had 12 months of warranty still once in the customers possession. So they were building in a fudge factor.

Terry

Offline KaiserFrazer67

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Re: AE 90 capacitor markings
« Reply #6 on: March 26, 2017, 06:07:37 PM »
Heard you were talkin' about my phone behind my back!  ;)  You made me hafta open it up again...  :D

I took a couple more pictures of the back of the dial and one of the circuit board; it looks as if there's a letter stamping on the board as well.
The dial one is extremely hard to read, and I'm a bit concerned that it may have gotten obscured by solvent when I sent all three 80/90 dials to Mark Treutelaar for cleaning/lubrication.  I never took notice of the codes, let alone their importance, when I first got into this.  At the time I was merely interested in getting the dials working again ASAP and knew nothing (at the time) of how to do it myself.  (Again, could've saved myself $45 plus shipping if I knew then what I know now, but, water over the dam...)

Dial code looks like it could be "OI7."  I don't think they skipped over letters just because they bore resemblance to numbers.  There also appears to be an "OI" code on the circuit board.  I don't believe it's a "10" because the numerals used in many areas look more like those used in the "Futura" font; e.g. where a numeral "1" is used, it has a serif on the top, whereas a letter "I" has no serifs.  Last pic shows the difference between what I think is an "OI" marking vs. the "10" marking for the L1 (ring) terminal.  (Yes, I color the screw heads with Sanford markers to help me remember how things are supposed to be hooked up.)  :D

I'm sorry that I can't help you out with the receiver and transmitter elements; not only are they both GTE-branded replacements, I remember approximately when it was done.  I was in my later teens, possibly in high school yet (mid-1980s), when the kitchen phone began to crackle. It got progressively worse and worse until it was impossible to have a decent conversation on it.  I remember Mom and I badgering the heck out of Dad to call GTE and get it fixed, which he finally relented and did--after at least two, maybe three months of this, IIRC.  I love and miss my Dad, and wish his memory no ill, but that's the way he was--he didn't want to spend money having someone else come and repair something unless he absolutely had to.  I remember when the service rep came to fix it.  He unscrewed the transmitter cap and switched out the transmitter:  "It just needs a new one; they only last so long," and he also switched out the receiver element for good measure, just to insure we wouldn't have any more problems.  I even remember saying to him, "THAT'S IT?!? THAT'S ALL IT WAS?!?"  Over two months of enduring that, just to find out the fix was that easy, and that cheap.  If they charged us anything, it was pennies--he wasn't there ten minutes, since he seemed to know what was wrong right away and he had the parts with him.  Phone worked fine after that, and it still does. 

Every phone does have a story...  and sometimes it makes you roll your eyes and shake your head...  ::)

P. S.  So "CXX" means a phone shipped without a ringer, for the ringer to be installed by the TelCo.  I guess the $64,000 question I have is:  How the heck can what appears to be a frequency ringer work perfectly fine on our standard POTS line since 1968?
« Last Edit: March 26, 2017, 06:32:07 PM by KaiserFrazer67 »
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

Offline AE_Collector

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Re: AE 90 capacitor markings
« Reply #7 on: March 26, 2017, 07:49:44 PM »
Thanks Tom!

We are all still learning this stuff here too. I just learned that there can be "two letter" codes on the network PCB. I hadn't noticed that before but then for some reason I hadn't looked very closely even though I have seen them on some of the potted networks. Certainly looks like OH EYE to me and I should be 1966 the way we are leaning at the moment. We haven't really got a handle on the first letter "O"...whether they started with A at the beginning of January (or not....could have been a year that ended say March 31 too) and if it did start at the beginning of January did it increment every other week using up exactly 26 letters in 52 weeks? If so, "O" would be in August where as the phone is dated October. But, if these were pre coded as they were made and tested(?) then a month or two wouldn't seem unreasonable to have the parts in stock in boxes waiting to be put into phones, in this case a phone that wound up with 10-66 on the base.

Who was your telco back in the 60's? If independent using AE phones, quite possibly a Step by Step office then eventually converted to electronic. I think someone, probably Unbeldi reported what your office switch is now. It may have been GTD5 in which case very likely an AE operating company. Straight Line ringers are more tolerant of different frequency but your 30 cycle ringer must be seeing 30 cycle ringing or something very close to that. It seems surprising that it has a nice strong ring but not as surprising as if it were a higher frequency ringer than 30 cycle.

I'm in a GTD5 office so I would try a 30 cycle ringer on for size BUT, I'm in a remote which isn't AE. Likely a SLC2000 so me testing would indicate nothing about your scenario though you could be on a remote as well.

Thanks again for the additional info!

Terry

Offline KaiserFrazer67

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Re: AE 90 capacitor markings
« Reply #8 on: March 26, 2017, 11:19:28 PM »
Thanks Tom!

We are all still learning this stuff here too. I just learned that there can be "two letter" codes on the network PCB. I hadn't noticed that before but then for some reason I hadn't looked very closely even though I have seen them on some of the potted networks. Certainly looks like OH EYE to me and I should be 1966 the way we are leaning at the moment. We haven't really got a handle on the first letter "O"...whether they started with A at the beginning of January (or not....could have been a year that ended say March 31 too) and if it did start at the beginning of January did it increment every other week using up exactly 26 letters in 52 weeks? If so, "O" would be in August where as the phone is dated October. But, if these were pre coded as they were made and tested(?) then a month or two wouldn't seem unreasonable to have the parts in stock in boxes waiting to be put into phones, in this case a phone that wound up with 10-66 on the base.

Who was your telco back in the 60's? If independent using AE phones, quite possibly a Step by Step office then eventually converted to electronic. I think someone, probably Unbeldi reported what your office switch is now. It may have been GTD5 in which case very likely an AE operating company. Straight Line ringers are more tolerant of different frequency but your 30 cycle ringer must be seeing 30 cycle ringing or something very close to that. It seems surprising that it has a nice strong ring but not as surprising as if it were a higher frequency ringer than 30 cycle.

I'm in a GTD5 office so I would try a 30 cycle ringer on for size BUT, I'm in a remote which isn't AE. Likely a SLC2000 so me testing would indicate nothing about your scenario though you could be on a remote as well.

Thanks again for the additional info!

Terry
Our TelCo was always General Telephone/GTE, which explains the AE equipment; although I'm finding out that evidently, despite being a subsidiary company, the General must not have had an exclusive lockdown on AE equipment like Ma Bell did with Western Electric.  Oakfield's telco was independent waaaay back in the day, but the General System took it over before we moved here.  It's possible they may have just continued some of the previous practices?  I'm in the process of trying to find out when the takeover took place.  Trouble is, we haven't had much in the way of historical interest in our little hamlet until very recently, and what meetings are finally taking place after all these years are happening when I'm at work on 2nd shift...  :P  Most of the folks involved in the local telco back in the day are long gone, I'm afraid.

I actually was able to look up our current CLLI code and switch info, and thankfully I wrote it down, because I can't find the site anymore!  Complete CLLI is OKFDWIXADS0 (digital switch zero) and the current switch type is GTD5EAX.  And my telco, which went from GTE to Verizon to the current Frontier, still has the original CO right up on the south end of town, about a 15-20 minute walk from me (less than a half-mile).  Copper from there down to the house.  I don't think too many folks can say that anymore in this day and age!

I probably should tell you that I did have to tune the 30~ ringers a bit, as they vibrated, but didn't ring when I hooked them back up around a month ago after about 20 years of not being used. (This was after I got the dials refurbished.)  Not really understanding what was going on--to me, a ringer was a ringer; I knew nothing of frequency vs. straight-line ringers, and I had just put the failure of the ringers down to the coils aging from the phones being in storage all this time.  It was a simple matter of moving the gong positions and adjusting the position of the plate relative to the coils, which got them ringing nice and loud again.  That also explains why I couldn't get the 40~ ringer tuned on the AE40 I just got from Marie.  Again, it would vibrate a bit, but not ring.  The only way it would ring is if I took all the tension off the spring plate and adjuster wheel and left the nut loose so there was nothing holding the spring plate in place.  It would then ring, but unlike the 30~ ringers in the other phones, the plate wasn't fastened down at all and would soon vibrate out of position.  I was able to "tune" the 30~ ringers enough to make them work well, and still manage to secure the adjusting wheel and locknut on the back of those ringers so they wouldn't be sloppy.  As for the 40~ ringer, IIRC someone had posted on the forums how they took a Dremel tool and cut slots in their spring plate so that there was enough flex to allow their frequency ringer to work normally, yet still secure the back plate.  I will try to find that thread again.

So then we were a step-by-step (mechanical) office which is now electronic/digital.  That makes sense, which explains why the 30~ ringers didn't work when I tried them again after all this time.  The switching had changed, not the condition of the ringers and coils.  I understand that now...  And...  it also explains why there wasn't any problem with the phone which had "S.L." on the ringer...  ::) 

We took our AE phones out of service sometime in the 1990's.  Mom's arthritis was getting the best of her, and she wanted a push-button phone.  By that time, a person could (finally!!) get one from the electronics/home entertainment section of the department store, so we got a few, and replaced the AE 80s, whose dials were starting to get sluggish.  I do remember having to keep the switch on "dial pulse" for the longest time, though.  The first time I was ever laid off and had to call in my unemployment, I had to dial the state UC office on dial pulse, switch to touch-tone to navigate the menu system, then remember to switch it back to dial-pulse after I was finished!  I think it was shortly after that (1995) when we finally had full DTMF capabilities here in Oakfield.  By that time, the dial on the kitchen phone had gotten pretty sluggish as well, so we just used it for answering calls.  (I remember having to follow the dial back with my finger to get it to work fast enough to dial out!)  About that same time, Mom had a series of strokes which put her in a nursing home for the remaining 6 years of her life...  :'(  I took the kitchen AE 90 down, installed a modular wall phone plate (the 90 was hard-wired and mounted right to the wall), and hung one of those Crosley-style repro wooden wall phones there with the push-button "fake rotary" dial, old-style handset and note box below.  It's there to this day, until I get a backboard and notebox made for the AE90.

Anyway...  if I was able to tune my 30~ ringers to work with a GTD5EAX switch at the CO, and yours has the same switch, you should be able to tune your 30~ ringers too by moving both the gong positions and the distance between the back plate and the coils.  That's really all I did, and it worked without me even realizing at the time why!  ;D
« Last Edit: March 26, 2017, 11:22:02 PM by KaiserFrazer67 »
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Offline KaiserFrazer67

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Re: AE 80/90 capacitor markings on KF67's phones
« Reply #9 on: March 26, 2017, 11:57:14 PM »
Okay; I'm going to expand this thread to include the two AE 80s from my collection.  Take the info for what it's worth; if these are indeed refurbs that were issued to us, as has been suggested, all bets are obviously off.

First up are the pics from the older and nicer of the two AE 80's which, just for my reference, we'll call "Dad's Phone" since it was in the master bedroom and he used it the most.  (This is the one which has the sticker on the handset.)

1) Base of the phone;

2) Back of the dial.  This one was stamped in a position where I had to remove the square mounting plate.

3) Straight-line ringer and capacitor codes;

4) Receiver and transmitter, noticing the codes don't match the rest of the phone.  I do know that they are the ones which have always been in the phone as long as we've had it.

5) A shot of the innards; I gather this is what they mean by a "potted transmission unit" as opposed to the printed circuit board.  I could not find any codes on the molded plastic block anywhere; the only things printed on it were the wire terminal positions (which are also molded in) and the part number.
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

Offline KaiserFrazer67

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Re: AE 90 capacitor markings
« Reply #10 on: March 27, 2017, 12:09:43 AM »
And finally, the one I'll call "Mom's Phone" because since it was a "floater" between the foyer/living room and the "den," she used it the most.  It was also the most-used of the three original phones.

1) Base of the phone, showing the codes.  I had to hold the phone at an odd angle to even see the code, let alone photograph it.  For some reason, it was stamped in such a way that I thought there wasn't even a code until I saw it in the right light.

2) Back of the dial.  Unlike the other, they had the foresight to stamp this one on the mounting frame rather than on the dial itself.

3) 30~ ringer with capacitor codes.

4) Circuit board with "1 AK" in two lines stamped on it.  I tried to photograph what appears to be the model of the circuit board: "WA1154A  ISS".
« Last Edit: March 27, 2017, 02:18:31 PM by KaiserFrazer67 »
-Tom from Oakfield, Wisconsin --  My CO CLLI & switch: OKFDWIXADS0--GTD-5 EAX

"Problems are merely opportunities in workclothes." -Henry J. Kaiser

unbeldi

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Re: AE 90 capacitor markings
« Reply #11 on: March 27, 2017, 10:46:38 AM »
I probably should tell you that I did have to tune the 30~ ringers a bit, as they vibrated, but didn't ring when I hooked them back up around a month ago after about 20 years of not being used. (This was after I got the dials refurbished.)  Not really understanding what was going on--to me, a ringer was a ringer; I knew nothing of frequency vs. straight-line ringers, and I had just put the failure of the ringers down to the coils aging from the phones being in storage all this time.  It was a simple matter of moving the gong positions and adjusting the position of the plate relative to the coils, which got them ringing nice and loud again.
The better and more correct way of adjustment is to move the weight on the clapper just a tiny but toward the end of the clapper rod. The weight usually has a lock-down screw that can be loosened to permit tuning.  Longer clapper and more weight -> lower frequency, shorter and lighter -> higher.  In addition, the AE ringers have an adjustment screw for tension of vibrating reed which can then be used for fine tuning.

This actually changes the resonance frequency of the ringer and provides full power for ringing without adjusting the gongs.

Quote
That also explains why I couldn't get the 40~ ringer tuned on the AE40 I just got from Marie.  Again, it would vibrate a bit, but not ring.  The only way it would ring is if I took all the tension off the spring plate and adjuster wheel and left the nut loose so there was nothing holding the spring plate in place.
Try adjusting the length of the clapper, but usually the rod is not long enough to bring 40 Hz ringers back to 20 Hz resonance, IIRC.

Offline mentalstampede

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Re: AE 90 capacitor markings
« Reply #12 on: March 27, 2017, 11:23:41 AM »
Depending on what frequency you have, a capacitor change may also be required to get a frequency ringer to respond to 20~. I had a 50 cycle ringer I was playing with and my electrical engineer of a brother informed me that the value of the capacitor was acting as a low frequency AC filter and preventing anything less than 40~ or so from even getting to the coils.
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Offline AE_Collector

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Re: AE 90 capacitor markings
« Reply #13 on: March 27, 2017, 11:57:23 AM »
I was thinking these phones seem like they may have been back through the shops (because of the variations in some of the two letter codes and the date on the base) before being installed at your parents home. I went back to your first post in your phone collection topic to see that indeed they were installed in July 1968 or thereabouts. So they were likely all fairly new but previously enjoyed phones when installed at your parents in 1968.

All my speculation here is an attempt to support the theory that AE's coding odometer rolled over to A=1958 with the right hand letter of the "two letter code" being the year.

The EK on the ringer is correct for 1968 when the phone was installed in 1968, maybe March (ish) for a manufacture date. But the phone is coded SL for a Straight Line ringer from the factory originally. Must have been SL when ordered, changed to a frequency ringer at its initial install elsewhere and then back to SL at the rehab shops and installed as a SL ringer phone in 1968. I'm thinking that if you were in a SxS office in 1968 you may have been in a 30~ connector group even though you had a private line. Thus they would give you 30~ ringers but it looks as though SL ringers were close enough to work as well.

The dial with EE, the second E should be 1962 so original to the phone and the first E again....maybe March which seems a little bit early in 62 for a phone ultimately dated July but who knows. Maybe the beige number plate was on the dial already and they were so busy making the wild 60's colored phones that they didn't get back to making more in beige 80's for a month or two. All speculation of course but for the most part, these codes and dates "work".

The 80's beige case was quite likely replaced at hehab time as it is notched for both back and side handset cord exit. Yet they stuck with the original chrome plungers. No need to toss them in favour of clear plastic plungers ...fortunately!

AE_Collector
« Last Edit: March 27, 2017, 11:59:53 AM by AE_Collector »

unbeldi

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Re: AE 90 capacitor markings
« Reply #14 on: March 27, 2017, 12:00:50 PM »
Depending on what frequency you have, a capacitor change may also be required to get a frequency ringer to respond to 20~. I had a 50 cycle ringer I was playing with and my electrical engineer of a brother informed me that the value of the capacitor was acting as a low frequency AC filter and preventing anything less than 40~ or so from even getting to the coils.

The impedance of a capacitor varies smoothly with frequency, so there is no real cutoff.  But it is correct that one has to observe that the total impedance of the ringing bridge does not exceed a certain value above which the power delivered to the ringer is no longer sufficient to excite it. The correct value of the capacitor depends not only on frequency but also on the impedance of the ringer coils, which AE also varied in their ringers.
Here are some examples of common Western Electric straight-line ringers, impedance vs frequency from this forum topic:

From this we see that the range in impedance for those ringers varied from about 10 kΩ to 40 kΩ.  Since it would be increasingly harder to deliver enough power to the ringer through a 40kΩ impedance, the ringing voltages were often increased successively for the higher frequencies.  So, the whole issue of adjusting frequency-selective ringers is a complex one and subject to trial and error depending on the current line parameters to which the phone is now connected.